238 PATHOGENIC BACTERIA. by Paquin. For a long period, donkeys were injected with increasing doses of tuberculin, in order that an antitoxin—antituberculin—might be generated in their blood. Experiments upon guinea-pigs showed that the serum was powerless to immunize against the tubercle bacillus, or to cure established tuberculosis. The serum, however, had the power of annulling the effects of tuber- culin upon tuberculous animals. While a failure experi- mentally, certain clinicians claim that in practice it ex- erts a beneficial action upon patients. Indeed, presuming that an antituberculin is formed, it is but natural that it should do good in all cases in which it is probable that the patient is poisoned by tuberculin or a similar product. Rather nearer the desideratum are the experiments of DeSchweinitz,1 who injected cows and horses with increas- ing quantities of bouillon cultures of a greatly attenuated tubercle bacillus, and subsequently found that the serum possessed the property of rendering guinea-pigs immune to the virulent bacilli. The Bacillus of Fowl-tuberculosis (Tuberculosis gal- linarum}.—The cases of tuberculosis which occasionally occur spontaneously in chickens, parrots, ducks, and other birds were originally attributed to the Bacillus tuberculo- sis hominis, but the recent works of Rivolta, Mafucci, Cadio, Gilbert, Roget, and others have shown that, while very similar in many respects to the Bacillus tuberculosis, the organism found in the disease of birds has distinct peculiarities which stamp it a different variety, but not a separate species. Cadio, Gilbert, and Roger succeeded in infecting fowls by feeding them upon food containing tu- bercle bacilli, and keeping them in cages in which dust containing tubercle bacilli was placed. The infection was aided by lowering the temperature with antipyrin and lessening vitality by starvation. Morphologically, the organisms are similar, the bacillus of fowl-tuber- culosis being a little longer and more slender than its ally. 1 Centralbl.f. Bakt. und Parasitenk., Sept. 15, 1897, Bd. xxii., Nos. 8 and 9.